Solid or solid-like, cake cosmetic products, such as make up preparations (e.g. face powder, powder foundation, eye shadow, mascara, rouge and the like) are conventionally produced by filling a cosmetic powder into a metal or plastic pan or case followed by molding the powder by a press. In particular, the conventional manufacturing process for preparing cosmetic products includes mixing pigments, and extender pigments and then atomizing them until the colors are well dispersed and uniform. Oily ingredients and auxiliary agents, such as anti-bacterial agents, are added to the pigments and extender pigments and mixed and are atomized to disperse the oily ingredients. The resulting mixture is then screened and further mixed until a uniform cosmetic powder is obtained. The cosmetic powder is filled into a pan or case and molded by a press.
This conventional process has several disadvantages:
i) Pigments and extender pigments have inherent strong hydrophilic properties; whereby, they will fade and/or discolor, when contacted by perspiration, unless they are specially treated.
ii) The percentage of out-of-specification product is unacceptably high due to the non-uniformity of surface-color and/or surface-hardness of the molded cosmetic product. PA1 iii) Multi-color molding and complex shape molding are quite expensive because of the cost of the shaping-mold, which is typically machined from metal. PA1 iv) High labor costs are incurred, arising from the manual labor needed for adjustment and maintenance of equipment and the supply of bulk powder. PA1 v) The loss of cosmetic powder during the molding process is significant. PA1 vi) The work environment is undesirable due to the exposure of the workers to powdery dusty pigments and extender pigments. PA1 a) Silicone fluids: Methicone; Dimethicone; Cyclomethicone; Phenyl Methicone (Methylphenyl Polysiloxane); and other cosmetically acceptable silicone fluids; PA1 b) Hydrocarbons: Mineral oil; Petrolatum; Isobutane; Isododecane; Isoeicosane; Isohexadecane; Isopentane; Paraffin; Squalane; Squalene; and other cosmetically acceptable hydrocarbons; PA1 c) Vegetable and animal oils: Lanolin oil; Sunflower oil; Caster oil; Olive oil; Wheat germ oil; and other cosmetically acceptable vegetable and animal oils; PA1 d) Fatty acids: isostearic acid; myristic acid; stearic acid; and other cosmetically acceptable fatty acids; PA1 e) Esters: Mono-, di-, triglycerides; Octyldodecyl myristate; octyldodecyl oleate; octyldodecyl erucate; octyldodecyl ricinoleate; octyldodecyl laurate; octyldodecyl palmitate; octyldodecyl stearate; octyldodecyl isostearate; Hexyldecyl myristate; hexyldecyl laurate; hexyldecyl palmitate; hexyldecyl stearate; hexyldecyl isostearate; Neopentyl glycol dicaprate; neopentyl glycol diheptanoate; neopentyl glycol diisostearate; neopentyl glycol dilaurate; neopentyl glycol dioctanoate; Trioctanoin; isononyl isononanoate; and other cosmetically acceptable esters; PA1 f) Ethers: Ethylene glycol; propylene glycol; butylene glycol; Polyethylene glycol; polypropylene glycol; and other cosmetically acceptable ethers; PA1 g) Polyols: Glycerin
It has previously been proposed to use pigments that have been made hydrophobic to solve problem (i). For example, pigments or extender pigments and/or substrates which are surface-treated with silicone are strongly hydrophobic and can be used to prevent color fading and to improve the duration of use before reapplication. They can also be used for two-way cake (wet/dry application) cosmetics.
While the use of polysiloxanes ameliorates problem (i), the molding process becomes more complex and time consuming, and problems (ii), (iii), (iv), (v), and (vi) remain unsolved.
There have been some suggestions to solve problems (ii), (iii), (iv), (v), and (vi). For example, Japanese Patent 07-29904 and U.S. Pat. No. 4,967,810 suggest the use of a slurry in which pigments, extender pigments and/or substrates, and oily ingredients are dispersed in an organic solvent for injection into the pan or case by an injection machine. These proposals may reduce the severity of problems (ii), (iii), (iv), and (v), but problem (vi) remains unsolved. Further, the choice of usable oily ingredients is restricted depending on the kind or nature of the organic solvent used. For example, non-uniformity of the product is observed when an alcohol is used as the organic solvent with a silicone oil as the oily ingredient of the cosmetic product.
In parent patent application U.S. Ser. No. 08/658,461, now U.S. Pat. No. 5,897,868 ('868 patent), a simplified process is described, to decrease the labor intensity of the conventional processes, to improve the work environment, and to provide a smooth, adhesive, spreadable, and long-lasting cosmetic product.
The invention of the parent '868 patent was based upon the discovery that when the pigments or extender pigments and/or substrates are made hydrophobic in an aqueous environment with an agent having a lipophilic moiety, such as water-insoluble metal salts of fatty acids, acylamino acids, hydrogenated lecithin, acyl collagen and the like, and rinsed and dried but not completely dried, the pigments remain hydrophilic until full drying. In such state the oily materials are added and the mixture thus formed is kneaded to form an aqueous slurry, the oily materials are uniformly bound to the surface of the pigments and extender pigments and are not disassociated. The parent '868 patent thus provided an aqueous slurry for cosmetic products with good dispersal characteristics (without the need for any irritating surfactants for the purpose of dispersing pigments, as is normally required for acceptable dispersal), which comprised particles of pigments and/or extender pigments having a lipophilic moiety attached-to-the surface thereof. This was in contrast to the simple non-attached coating as disclosed in the various Miyoshi U.S. Pat. Nos. 4,606,914, 4,623,074 and 4,863,800, used with the same general materials but which do require the use of surfactants for effecting a dispersion in an aqueous slurry; and a cosmetically acceptable oily ingredient dispersed in a liquid suspending medium consisting essentially of water. Though effective in processing and use and with superior resultant products, transportation of the slurry described in parent '868 patent is costly, due to the weight of liquid suspending medium.